Drug interactions
Flecainide + Fluoxetine
Severity: Major
Flecainide and Fluoxetine: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Fluoxetine strongly inhibits CYP2D6, the main pathway for flecainide metabolism, and can raise flecainide concentrations. This may lead to conduction slowing, QRS widening and ventricular arrhythmias. Fluoxetine itself has a small QT effect.
What this interaction means in plain words
Flecainide and Fluoxetine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Flecainide belongs to Cardiovascular; Fluoxetine belongs to Central Nervous System.
Why it happens
Inhibition of CYP2D6-mediated flecainide metabolism, increasing flecainide exposure.
What to do
Monitor ECG (PR, QRS) and flecainide plasma levels, and reduce flecainide dose as needed. Consider an antidepressant with less CYP2D6 inhibition, such as sertraline at low doses or citalopram-class alternatives with caution.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Flecainide
- Flecainide + Nirmatrelvir Contraindicated
- Flecainide + Nirmatrelvir / ritonavir Contraindicated
- Flecainide + Pimozide Contraindicated
- Flecainide + Ritonavir Contraindicated
- Flecainide + Thioridazine Contraindicated
- Flecainide + Tipranavir Contraindicated
Other interactions of Fluoxetine
- Fluoxetine + Isocarboxazid Contraindicated
- Fluoxetine + Mavacamten Contraindicated
- Fluoxetine + Methylene blue Contraindicated
- Fluoxetine + Phenelzine Contraindicated
- Fluoxetine + Pimozide Contraindicated
- Fluoxetine + Rasagiline Contraindicated
Frequently asked questions
Can I take Flecainide with Fluoxetine?
MediHelp rates the interaction as major. Flecainide and Fluoxetine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Fluoxetine strongly inhibits CYP2D6, the main pathway for flecainide metabolism, and can raise flecainide concentrations. This may lead to conduction slowing, QRS widening and ventricular arrhythmias. Fluoxetine itself has a small QT effect.
How serious is the interaction between Flecainide and Fluoxetine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor ECG (PR, QRS) and flecainide plasma levels, and reduce flecainide dose as needed. Consider an antidepressant with less CYP2D6 inhibition, such as sertraline at low doses or citalopram-class alternatives with caution.
What other medicines interact with Flecainide?
MediHelp also lists interactions of Flecainide with, for example, Nirmatrelvir, Nirmatrelvir / ritonavir, Pimozide. The full list is on the Flecainide page.
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